The present invention is directed to a mattress structure which is resistant to catastrophic incineration when subjected to flame. More particularly, the invention is directed to a mattress having a novel binding assembly linking the upper and lower surfaces of the mattress to the horizontal ticking components surrounding the mattress.
Catastrophic fires involving mattress components are too frequent in occurrence. While all mattress fires are dangerous, a conflagration which impinges upon the binding seam linking the upper and side ticking components is far more dangerous then a fire which penetrates a central portion of the ticking. A centrally disposed burn-through is likely to result in smoldering confined to the ticking and perhaps a small amount of the batting which registers with the penetration. Such burn-through occurrences, which often result from a cigarette contacting the mattress, are typically, sufficiently slow-burning as to arouse the occupant of the bed before significant damage results.
A far more dangerous conflagration will arise when the flame and/or burn-through encounters the binding seam linking the upper and side ticking. This is because when the binding is compromised, compressed batting will rapidly release the connection between ticking components enabling the batting to extrude through the opening. The extruded batting, typically formed of cotton, polyester, or many types of materials including foams, is especially subject to rapid burning when expanded, increasing exposure to oxygen. There is accordingly a need for an improved binding assembly linking the major surfaces of the mattress to the ticking, which binding is resistant to rupture, and thus reducing the possibility of the consequent extrusion of the batting, when the binding is subjected to high heat and flame conditions.
Conventional known mattress seam constructions for linking the side ticking to the major mattress surfaces, are formed by placing the margins of the top and side ticking into juxtaposed relation either in edge to edge relation or with each of the tickings rolled back to provide double layers. Thereafter, a decorative tape is superposed over the ticking edges and a thread is stitched to the assembly, the thread penetrating the tape, the edges or folds of the two ticking components, and thereafter exiting through the tape. The physical structure of the binding of the instant invention is essentially conventional corresponding to the description above.
A number of patent references developed by a search of the prior art have been located. The references developed are noted below:
U.S. Pat. No. 3,889,305 is directed to a mattress having a fabric to be used as an edging. The fabric comprises at least 50% monofilaments and optionally some spun yarns, the composition of the filaments being one or more of those set forth at column 9, lines 43 et seq. of the patent. The lift of the fabric is said to be such that the ratio of fabric thickness to average thickness of the monofilaments is from 2.5 to 1 to 4.5 to 1, the fabric weighing between 6 and 20 ounces per square yard.
U.S. Pat. No. 4,430,765 discloses a flame-retardant mattress of the type which is free of metallic components, i.e., for use in prisons or other environments where the metals could be used as weapons. This patent teaches the use of a tubular, perimeter portion, which incorporates a fire-retardant such as boric acid.
U.S. Pat. No. 4,294,489 is directed to a process for improving the flame resistance of certain fabrics. In accordance with this patent a layer of neoprene foam is applied to the fabric, the neoprene being capable of evolving water at combustion temperatures. The water is said to cool the affected area. The layer is said to form a thermally-insulating char which maintain its structural integrity.
U.S. Pat. No. 4,623,571 discloses a flame-proofing layer bonded to a reinforcing layer. The layers carbonize without melting.
U.S. Pat. No. 5,279,878 is directed to a flame barrier formed of non-woven fabric comprised of non-meltable partly graphitized polyacrylinitrile fibers bonded by a water jet needling technique.
U.S. Pat. No. 4,892,769 discloses a fire-resistant article namely a baby seat having a core comprising thermoplastic material having the fillers included therein such as wood or pulp. The fibers are deposited on a non-woven thermoplastic facing and heated to bind the core fibers to the thermoplastic sheet and to themselves. The integrity of the sheet is said to be maintained under high heat conditions. The seat includes a core having fire-resistant material, a liquid permeable facing sheet on one side and a liquid impermeable sheet on the other side.
Reissue patent 29,630 suggests rendering mattress fabrics fire-resistant by coating a surface of the fabric with a binding material having quantities of aluminum or graphite incorporated therein.
U.S. Pat. No. 4,746,565 is directed to a fire-retardant fabric comprising a self-extinguishing face fabric laminated to a glass fiber fabric. The glass fibers are coated to enable handling and prevent abrasion between adjacent glass yarns.
The present invention may be summarized as directed to a mattress assembly having improved binding seams linking the ticking component of the top and bottom surfaces with a side ticking. Still more particularly, the invention is directed to a mattress structure having a binding component resistant to rupture when exposed to high heat and flame.
Still more particularly, the invention is directed to a mattress structure having a binding which, while structurally similar to conventional mattress bindings incorporates as binding components polymeric materials which react synergistically to maintain the structural integrity of the connection between the ticking components for a relatively extended period as compared to binding structures heretofore known.
In accordance with the invention, the ticking margins to be connected are overlaid with a fire retardant fabric tape. The composition of the tape, preferably a polyester, is selected such that the same is thermoplastic and is subject to melt and flow at relatively low temperatures. The sewing thread employed to complete the binding structure comprises a thermo-setting polymer which chars at a temperature substantially higher than the melt temperature of the polymeric tape, i.e. a para-aramid.
It has been discovered that when a binding seam of a type described is subjected to flame conditions, the rapidly melting thermoplastic tape tends to flow and wick into the thermosetting sewing thread forming a protective layer or coating over the thread which renders the binding seam resistant to rupture over a relatively protracted period of time as compared to known bindings. Surprisingly, we have discovered that the combination of low-melt polyester tape and high-heat-resistant aramid, i. e. para-aramid and meta-aramid, sewing threads provides a superior performance to a combination in which the sewing thread is a thermoset aramid, i. e. para-aramid and the tape is a thermoset meta-aramid.
It is accordingly an object of the invention to provide a mattress having a binding resistant to separation or rupture when subjected to flame or high heat conditions. A further object of the invention is the provision of a mattress having a binding assembly comprising a low-melt flame-retardant thermoplastic material in combination with a sewing thread linking the binding components comprised of a high-heat resistant thermosetting material. A still further object of the invention is the provision of a binding assembly wherein the binding tape is comprised of a fire-retardant thermoplastic material which, when subjected to heat above its melt temperature, will flow or wick into and around the structural thread components and protect these components whereby the binding or seam is resistant to rupture for a period of time substantially longer than binding assemblies heretofore known.